Small RNAs Elevated in Patients’ Urinary Vesicles, Study Shows

Marisa Wexler, MS avatar

by Marisa Wexler, MS |

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An image of a person drinking from a glass and a view from behind shows his kidneys at work.

Levels of five small RNA molecules were found to be highly elevated in extracellular vesicles — small packets of cellular cargo — found in the urine of people with ANCA-associated vasculitis (AAV), a new study reports.

These preliminary findings indicate the impairment of these RNA molecules might be linked to disease-related processes in the kidneys of AAV patients.

The study, “Analysis of microRNAs in Small Urinary Extracellular Vesicles and Their Potential Roles in Pathogenesis of Renal ANCA-Associated Vasculitis,” was published in the International Journal of Molecular Sciences.

Extracellular vesicles are small bundles of cellular materials, such as protein and RNA, that are released from most types of cells and are involved in cell-to-cell communication. These small particles can be detected in many bodily fluids, including urine.

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An image of a person drinking from a glass and a view from behind shows his kidneys at work.

Small RNAs Elevated in Patients’ Urinary Vesicles, Study Shows

Since urine is easily collectable and is processed by the kidneys, an emerging area of research is exploring whether urinary extracellular vesicles, or uEVs, might be useful biomarkers of kidney disease.

AAV is an autoimmune disorder marked by blood vessel inflammation that often affects the kidneys, which contain a large number of blood vessels.

Scientists in the Czech Republic analyzed uEVs of 24 people with AAV, and 16 people with no known health problems who were similar in age. They specifically analyzed microRNAs found within uEVs. MicroRNAs, or miRNAs, are small RNA molecules that are important for regulating the activity of certain genes, and therefore the production of proteins.

“The miRNAs in uEVs had not yet been examined in association with their role in the pathogenesis [development] of AAV, and therefore we conducted this study,” the researchers wrote.

Scientists identified five miRNAs that were active at abnormally high levels in AAV patients: miR-30a-5p, miR-31-3p, miR-99a-5p, miR-106b-5p, and miR-182-5p.

One of these molecules, miR-30a-5p, has been shown to be elevated in uEVs in other kidney disorders, such as nephrotic syndrome and diabetic nephropathy.

“The elevated levels of other miRNAs included in our panel are unique for uEVs in AAV patients, and therefore their role in differential diagnostics deserves further study,” the researchers wrote.

Researchers also looked at the proteins these miRNAs are known to regulate. In total, these five miRNAs are involved in regulating 681 different proteins that have been implicated in a wide array of biological processes.

Several of these proteins are known to participate in kidney development and organizing the “cellular skeleton” that helps give cells their shape, the researchers noted. They suggested these findings could reflect changes in the cellular architecture of the kidneys as a result of AAV-related damage, though they cautioned that these preliminary results will require further validation.

“Further comparative studies that would also include patients with other proliferative glomerular diseases and would focus on the clarification of potential pathogenic [disease-related] roles of these miRNAs are needed regarding the practical application of this miRNA set in differential diagnostics and disease-progression monitoring,” they wrote.